Light aircraft are most often secured with ropes tied only at the aircraft
tiedown rings provided for securing purposes. Rope should never be tied
to a lift strut, since this practice can bend a strut if the rope slips
to a point where there is no slack. Manila rope shrinks when wet; about
1 inch of slack should be provided for movement. Too much slack will allow
the aircraft to jerk against the ropes. Tight tiedown ropes put inverted
flight stresses on the aircraft, many of which are not designed to take
such loads.

A tiedown rope holds no better than the knot. Antislip knots such as
the bowline or square knots are quickly tied and are easy to untie (figure
11-22). Aircraft not equipped with tiedown fittings should be secured
in accordance with the manufacturer's instructions. Ropes should be tied
to outer ends of struts on high wing monoplanes, and suitable rings should
be provided where structural conditions permit, if the manufacturer has
not already provided them.